Jon> On 13 Aug 1998, Jes Sorensen wrote:
>> No in user space - fbdev may use accel for things that can speed
>> up the console code, like recangular blitting and clearing, it does
>> not intend to provide some generic kernel accel API.
Jon> But is has in fact done so, by allowing for driver-specific
Jon> ioctls. That is one thing those ioctls be be used for.
Its possible, but it was not the intention.
>> When you want to have accel control in user space, you tell fbdev
>> and it wont use acceleration for the console until the user space
>> program finishes with it.
Jon> I assume by "user space" you mean X primarily.
Or something like libGGI.
>> We did not do that on purpose, ioctl == context switch and we
>> don't want that.
Jon> direct userspace access to accel registers == unsafe. *I*
Jon> don't want *that*. You can get quite acceptable speed out of
Jon> ioctls. Not the most speed possible, but in most cases that
Jon> isn't a concern.
Sorry, tough.
If you want to run X on broken hardware then you'll have to take the
risk. A context switch is not acceptable here and much worse, it will
require you to implement a zillion drivers for acceleration of various
chipsets which will lead to unnecessary code bloat.
Jes
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